45# is the grade of steel is a high-quality carbon structural steel, corresponding to Japanese standard S45C, American Standard: 1045, German standard C45. It is characterized by higher strength and deformation resistance than ordinary A3 steel.

Widely used in machinery, not heat treatment: HB < 229; heat treatment: normalizing; impact energy: Aku < 39J A high strength, plasticity and toughness is good, 45 # steel plate quenched without tempering, hardness greater than HRC55 (up to HRC62) is qualified, after heat treatment, re-quenching can reach HRC42-46, so that it can be guaranteed. It has good mechanical properties and can obtain surface hardness requirements. It is used to make small cross-section quenched and tempered parts with high load, large normalized parts with low stress, and surface quenched parts with low core strength requirements, such as pins, guide posts, dial needles, etc.